PROBLEM TO BE SOLVED: To provide an interdental cleaning instrument capable of enhancing an insertion property of a cleaning part in between molars.SOLUTION: An interdental cleaning instrument comprises a base part (10) and a cleaning part (20). The base part (10) has a shaft section (12) and a gripping section (14). The cleaning part (20) includes an insertion end section (12a), and is shaped to cover a section of the shaft section (12) having a dimension equal to or less than the axial dimension thereof. At least the shape of the base part (10) is set such that: while a section separated by 10 mm from the tip of the cleaning part is immobilized, a first pressing force is 0.3-1.4 N inclusive, which is required in pressing by 10 mm a section separated by 2.5 mm from the tip of the cleaning part； and while a section separated by 35 mm from the tip of the cleaning part is immobilized, a second pressing force is 0.5-2.5 N inclusive, which is required in pressing by 10 mm a section separated by 8.0 mm from the tip of the cleaning part.SELECTED DRAWING: Figure 1【課題】奥歯同士の歯間への清掃部の挿入性を向上可能な歯間清掃具を提供すること。【解決手段】歯間清掃具であって、基部（１０）と、清掃部（２０）と、を備え、基部（１０）は、軸部（１２）と、把持部（１４）と、を有し、清掃部（２０）は、挿入端部（１２ａ）を含みかつ軸部（１２）のうち軸方向の寸法以下の寸法を有する部位を被覆する形状を有し、清掃部の先端から１０ｍｍ離間した部位を固定した状態において、清掃部の先端から２．５ｍｍ離間した部位を１０ｍｍ押圧するのに必要な第１押圧力が０．３Ｎ以上１．４Ｎ以下となり、かつ、清掃部の先端から３５ｍｍ離間した部位を固定した状態において、清掃部の先端から８．０ｍｍ離間した部位を１０ｍｍ押圧するのに必要な第２押圧力が０．５Ｎ以上２．５Ｎ以下となるように、少なくとも基部（１０）の形状が設定されていること。【選択図】図１
